Improvement in hay-derricks



UNITED STATES PATENT OFFICE..

ISAAC VAN VOORHIS, OF HILLSBOROUGH, PENNSYLVANIA.

IMPROVEMENT IN HAY-DERRICKS.

Specifica-tion forming part of Letters Patent No. 69,375, dated.Oct-ober l., 1867.

To all whom it may concern:

p Be it known that I, ISAAC VAN VOORHIS, of Hillsborough, in the countyof Washington and State of Pennsylvania, have invented a new and usefulImprovement in Derricks and Hoisting Apparatus; and I do hereby declarethe following to be a full, clear, and exact description thereof,reference being had to the accompanying drawing, making part 0i' thisspecification, which is a side elevation ot' my improved derrick orapparatus for hoisting.

The nature ot' my invention consists in the construction of an improvedderrick for raising or hoisting large bodiesor heavy weights.

To enable others skilled in the art to make and use my invention, Iwill'proceed to describe its construction and operation.

The main post a, of any desirable length and. otsuflicieut size tosecure the requisite strength, rests on a turn-table ofthe ordinaryconstruc` tion, or on any other desirable foundation, and is securelyfastened thereto, or connected in such a way as to rotate at pleasure.It is usually made of uniform size its entire length with a square orrectangular transverse section. At or near its upper end, and attachedthereto, is a band, b, made sutciently large to encompass a similarpost, a', at or near the lower end ot' which, and attached thereto, is asimilar band, b', b and b being so-iitted as to allow the post a',sliding along the post c, to be raised or lowered at pleasure. In theupper end oi' the post a is a grooved or pulley wheel, c, over whichpasses a cord, rope, strap, or chain, d, one end ot' which is attachedto the arm e, which is hinged to the post c, and the other end to thearm c', hinged to the post a. The weight to be raised is attached at ornear the outer end of the arm c by the hook represented in Fig. 2, or byother similar device in common use, and the hoisting-power similarlyapplied to the other arm, c, by a rope or chain,f, which may be workedby a capstan or other equivalent device, or by hand, as preferred.

The devices thus described are adj usted to each other and to weight andpower in any desirable proportions, or they are so made that therelation of power, weight, and distance can be varied at pleasure, inaccordance with the generally-known principles governing the applicationof power by levers and pulleys. The points on the arm e at which therope d and the weight are attached, also the points on the opposite arm,c, for attaching the ropes d and j', may any and all be varied at thepleasure of the operator, or according to the amount of power which isavailable or the work to be done. YCommonly I provide two or more placeson each arm c and c', to which to attach the rope d. The places forhinging the arms c and c may also be varied at pleasure, in accordancewith the same general and wellknown laws. The derrick thus described isvery accurately balanced, and requires only to be braced or stayedsufciently to steady it from falling by its own weight or prevent itsswinging to either side when in actual use, unless the posts c and a areset obliquely, which is seldom, if ever, necessary.

By the devices thus described I secure a derrick or hoisting apparatusself-balancing, and either portable or stationary, and applicable to anyand all purposes oi' hoisting or lifting for which derricks areordinarily used, or for which hoisting apparatus is required. For thepurpose of raising the post a', I employ a screw, lifting-jack,pulley,vor any of the common mechanical powers in their ordinary formsoi' application, and hold it in position by screws g.

In the derrick as above described the two posts a and a. are not bothnecessary, though l generally so construct it. A single post may takethe place of the two, the pulley c be pivoted in its upper end, the armsc and c hinged toits opposite sides, and the mode ot' operation besubstantially the same. Nor do I limit myself to the method ot hingiugspeced in order to connect the arms c and e to their posts a and af, asI employ for that purpose any device in ordinary use which will give airm workingjoint. The post a may also be made in such a way that thepulley c can be hung higher or lower at any desirable point.

What I claim as my invention, and desire to secure by Letters Patent, is

A portable self-balancing derrick consisting of one or more uprightposts with arms hinged on opposite sides, such arms connected with eachother in the manner described, and the Whole operating substantially asand for the purposes above set forth.

In testimony whereof I, the said ISAAC VAN VOORHIS, have hereunto set myhand.

IsAAo VAN vooEHIs.

